Automatic control for humidifiers



June 30, 1925.

F. F. EBAHNSON AUTOMATIC CONTROL FOR HUMIDIFIERS Original Filed Aug. 15, 1918 2 Sheets-Sheet 1 abbomwa m June 30, 1925. 1,544,418 F. F. BAHNSON 1 I AUTOMATIC CONTROL FOR HUMIDIFIERS Original Filed Aug. 13, 1918 2 Sheets-Sheet 2 Patented June 30, 1925.

UNITED STATES FBEDERIC F. BAHNSON, OF WINSTON-SALEM, NORTH CAROLINA.

AUTOMATIC CONTROL FOR HUMIDIFIERS.

Original application filed August 13, 1918, Serial no. 249,697. Divided and this application flied September 11, 1922. Serial No. 587,632.

To all whom it may concern! Be it known that I, Fnnnnmo F. BAHNSON, a citizen of the United States, residing at Winston-Salem, in the county of Forsyth I and State of North Oarolina, have invented certain new and useful Improvements in Automatic Control for Humidifiers, of which the following is a specification.

This invention relates to improvements in the automatic control of humidifiers so that the relative humidity of the air may be maintained. at any desired point. Heretofore humidity regulation has been dependent on controlling devices which afiord pracll tically no intermediate steps between full operation of the humidifiers and entire stoppage of their evaporative effort. It is obvious that the effect of such control would inevitable be such as to cause a saw tooth record on a recording hygrometer.

It is the particular ject of this invention to provide controllin means actuated by the relative humidity o the air, whereby the evaporative effort of a humidifier is automatioally varied in amount in proportion to the requirements to be met. The desired result is accomplished by using a valve with a variable opening, the amplitude of such 0 ening being controlled positively and 80 directly by the effect of themoisture content of the air on aspecially designed hygrometric strip.

This control is peculiarly adaptable to humidifiers of the type disclosed in my Patent #1,267,166, and while that type is used in this disclosure for illustration, I do not limit myself to that particular application, as this control may be applied to any humidifying device whose humidifying action is proportional to the water supplied to it.

It will be understood that I do not limit myselfto the exact materials specified herein for the various parts of this device, and

that mechanical changes dictated by ease of manufacture or efficient operation may be made without departing from the spirit and scope of the invention.

That the construction and operation of u the device may be understood, reference is had to the accompanying drawings in which the same reference numbers always indicate the same parts.

Flgure 1 is a general view of the invention as applied to a humidifier of the. type disclosed in my Patent 1,267,166.

Flgure 2 is an elevation of the control alone. I

F gure 3 is a plan view ofthe control.

Flgure 4 IS an elevation of the hygrometrlc strip.

Figure 5 is a section showing the principal parts of the control.

I n the drawings 1 is a sheet metal case or guiding means for'air currents produced by fan 8, 2 1s a revolving disc to which near its center, water is supplied, andfrom which the water is thrown by centrifugal force against the annular row of obstructions 3, these obstructions being supported by and 7 integral with ring 4;. Motor 7 is used to rotate fan 8 and disc 2. Fan guard 9 protects the fan and assists in guiding the air currents.

The chief parts of the control are strip 10, 7 lever 16 of which is held in position upon a fulcrum 16 by spring 15 in s ring case 14, which in turn is held in a 0 amp 14: and valve 25 operated by lever 16 through valve stem 17 in any suitable manner.

10 is a long thin strip made preferably of one or more pieces sawed across the grain from the end of aboard of specially selected wood. By selection of wood to get substantially radial section I obtain a large total change of length in the strip for varying relative humidities. Other material than wood may be used, and in special applications the strip may be made of the same material as that worked in the room whose humidity it is desired to control.

Accuracy of control is accomplished by proper selection of material for strip 10, the degree of sensitivoness being determined by the length of strip 10. In practice I use a strip less than 1% of whose'total available change of length will move valve 25 from tight closure to full opening. -Itwill be noted that lever 16 is so proportioned V. and arranged that any motion of strip 10 is multiplied on valve stem 17. As shown, the motion of valve stem 17 1s about double that of strip 10, but this ratio may be changed as desired.

The action of the control is as follows:

Water is admitted from any convenient source through pipe 21 and hand operated valve 22 to chamber 19 in which is located strainer 20. When strip 10 'is dry from low humidity, valve 25 is open, the water passes to chamber 18 from which it is concucted through pipe 5 and nipple to disc 2. The opening from pipe 5 to mpple 6 1s of such size that the flow of water to the humidifier (disc 2 in this disclosure) can never exceed the maximum amount required for eflicient action. For the reason to be immediately stated, the valve opening 25, however, is made larger than the opening leading from pipe,5 to nipple 6. Ordinarily the range of motion of the valve stem 17 1s 11mited by set screw 26 so that the largest effective valve opening is substantially thesame as the opening ,between: pipe 5 and nipple 6. At times, however, it is advisable to open the valve 25 wide and allow an excess of water to pass into pipe 5 which water will fill the pipe 5 completely and pass out .through the free end 5 of the pipe 5. This pipe 5 having the shape ofan inverted U .acts 'as a siphon so that no water will pass through the nipple 6 to the disk 2, but that rather air will be sucked in through the. nipple 6 clearing it of trash or other obstructions thatmay settle therein. 7

It is understood that the opening be tween pipe 5 and nipple 6 may be made slightly larger than required for the efficlent operation of the humidifier. In .this

.- case the siphon arrangement acts as a safety device to prevent flooding. of the humidifier until the set screw 26 is set to properly limit the opening of the valve.

Strip 10 is free to move longitudinally in guides 11, except as limited by adjusting screw 13 and block 12 or other suitable mecl1anism. As the relative humidity of the air increases, strip 10 absorbs moisture, and expands, forclng down block 12, lever 16,- valve stem 17, closing valve 25. I have found by experiment that s'triplO soon assumes such a'condition that valve 25 has a practically constant opening jnst enough wate-rbeing permitted to reach disc 2, to hold the relative humidity of the room at the desired point. In other words, with constant conditions, valve 25 is automatically held at the proper degree of opening to supply to disc 2 just enough water so that the evaporation of water by the humidifier exactly compensates for the removal of moisture from the air in the room by leakage through walls or openings or by 'absorption of such water by dry materials.

The construction of strip 10 is such that changes of air condition readil and quickly.

cause change in its length. T is makes my control very quick acting. I,

It should be noted that the valve defines a steep cone and that the valve seat is correspondingly sharp-angled. While the range of movement of the valve stem between fully open and fully closed position is made short so as to obtain a quick control for a particular point of humidity, the change of the eflecti ve o ening is nevertheless very gradual throug out the range of movement. It thus can be readily seen that the arrangement accomplishes an accurately graduated .variation in the flow of water within a very small range of motion of the hygrometrically responsive ele- To avoid packing friction on the valve stem, I make valve stem 17 in two pieces,

which, when screwed together, clamp betwee-n them the center of flexible diaphragm 27, whichis held at its outer edge by cap 28. This construction permits freedom of movement by valve stem 17 along its axis, keeping it centered in the valve, and at the sanlie time chamber 18 is rendered water tig it.

Adjusting screw 13 is provided to permit setting the control for anv relative humidity desired by which strip 10 must expand in order to close valve 25.

Should the relative humidity fall very. low, strip 10 simply contracts, and remains loose in guides 11. If the relative humidity rises beyond the closes valve 25, further expansion of strip 10 simply pushes down lever 16 a ainst the tension of spring 15, away from fu crum 16', into a space provided for such movement by a deep slot 16? in sup orting block 23.

If it is desired to flus out valve 25, cha n ber 18, pipe 5 and nipple 6, the end of lever changing the distance through.

point at which strip 10 16 opposite the valve stem is pulleddown. The attachment of spring 15 thus becomes the fulcrum, the other end of lever 16 rises, and with it valve stem 17, o ning valve 25 to the limit imposed by diapli i'agm 27 striking the central shoulder of this wide opening of valve 25 the siphon efl'ect is produced as described above.

It will be noted from Figure 1 which shows,

the preferred p'ositionof the control that the.

air which affects strip 10 is that from the cap 28. With room itself, and not air which is charged with moisture from the humidifier. The control should always be so placed whether on my humidifier or any other, or mounted at a distance, that it is surrounded by air in the condition of the average of the room and since the accuracyof any hygrorneter is dependent upon active circulation of air over or around it, this control should, wherever fans are in operation, be laced in the air current produced by such ans.

It is understood that the expansive movement of the hygrometric strip or strips may be magnified to a greater extent than shown and the valve so designed as to change the valve opening very gradually so that the sensitiveness of the hygrometric control may be increased to any desired degree.

Experimental tests of the invention, as above described, through a period of months show that this control gives a remarkably smooth and uniform record on a recording hygrometer placed in the room controlled by my invention.

Various changes may be made within the scope of the invention.

This application is a division of my application Ser. No. 249,697 filed Aug. 13, 1918, now Patent 1,439,217 granted December 19, 1922.

I claim:

1. In a humidifier, the combination with a conduit and valve mechanism for controlling the same, of a hygrometrically responsive element mounted to expand in one direction, a lever bodily movable in the plane of movement of the said element and disposed to be acted upon intermediate its ends by the element, means disposed near one end of the lever for limiting the movement thereof toward the said element, resilient means for drawing the lever against said limiting means and means connected with the other end of the lever for translating motion thereof to the valve mechanism.

2. Apparatus according to claim 1 in which the limiting means has a pivot edge and the lever has a notch receiving the edge.

3. Apparatus according to claim 1 in which the means for translating the motion of the hygrometrically responsive element includes a member mounted for reciprocating movement and a loose pivotal connection between the lever and the said member.

4. Apparatus according to claim 1 in which the means for translating the motion of the hygrometrically responsive element includes a member mounted for reciprocating movement, means for limiting the movement of the .said member and a loose pivotal connection between the lever and said memher.

5. Apparatus according to claim 1 in which the meansfor translating the motion of the hygrometrically responsive element includes a member mounted for reciprocating movement, means for limiting the angular movement of the lever in the direction toward the hygrometric element and a loose connection between the lever and the said member.

6. Apparatus according to claim 1 including a guide in which the hygrometrically responsive element is freely movable and means for adjustably limiting the movement of the said element in a direction away from said lever.

7. In a humidifier, the combination with a conduit and valve mechanism constructed and arranged to have a relatively short movement between fully open and fully closed position, of a hygrometric strip having a high rate of expansive movement and means for translating the movement of said strip to the valve mechanism, said means including resilient means adapted to yield to the expansive movement. of the hygrometric strip when the valve has reached closing posltion.

8. In a humidifier, the combination of a conduit, valve mechanism having a relatively short movement between fully open and fully closed position, but constructed to gradually vary the effective opening within its range of movement, a hygromctric strip having a high rate of expansive movement, means for translating the movement of the said strip to the valve n'iechanism and means for adjusting the said strip relatively to the translating means.

9. Apparatus according to claim 8- in which the translating mechanism includes resilient means adapted to yield to the expansive movement of said strip when the valve has reached closing position.

In testimony whereof, I atfix my signature.

FREDERIG F. BAI'INSON. 

